Any Cory Cats That Don't Need To Be In A Group

[rebrn]

Hello, I was thinking of adding 2 cory catfish to my 12 gallon tank for a little bit of interest at the bottom of the tank. However, all of the ones I am aware of really should be kept in groups of 4 or more. I was wondering if there is any cory cats that would be ok to keep as a pair, or anyother bottom dwellers that would work in a 12 gallon tank. I am looking to keep roughly 2-3 max as I already have 9 Harlequin Rasboras and 2 Olive Nerite snails.

Thanks


Edit: I just found the pygmy cory - it said they grow to about an inch, so would it be ok to keep 4 of them in the 12 gallon with 9 harlequin rasboras and 2 olive nerite snails? Also does any one know where to get them, my local stores don't carry them, also I can't seem to find any store on line (including aqua bid) that has them.

 

[nmonks]

No, all Corydoras need to be kept in groups of five or more specimens *per species* (by all means keep two or more species, but at least five of each kind). Keeping these catfish in smaller groups just isn't fair.

In a 12-gallon tank you could keep half a dozen Corydoras habrosus or some other mini species without problems. I would *strongly* recommend keeping more than that though. These tiny catfish are (understandably!) shy and nervous, and in small groups simply hide away. When kept in big groups, i.e., 10 or more, they're entirely different, and will even swim about in a school in midwater, almost like tetras. I keep a related genus, Aspidoras pauciradiatus, that is a bit more delicate but otherwise kept in the same way.

If you want a singleton catfish for an aquarium this small, I'd recommend whiptail cats. Indeed, two or three specimens would be fun too. Rineloricaria parva for example is extremely hardy, eats bloodworms and pellets readily, and is great fun to watch as it walks (rather than swims!) along the bottom. All whiptails prefer a sandy substrate, so if that's an option, it's well worth doing.

Cheers, Neale

 

[OldMan47]

If you are in the US, some of the LFS, the real ones not the chain stores, carry the Corydoras habrosus. By appearance they look almost like a miniature peppered cory. This is one of mine and the only pygmies I found locally. I got my hastatus and pygmaeus from internet stores.

 

[waterdrop]

I have read this grouping information about Corys several times now on TFF and Neil, you've really written it up nicely there! Every time I read it I just shake my head in sadness, remembering all the tanks I had back in the 60's, so many of which had one or two or maybe at most 4 corys who were always shy and staying pretty still in the aquarium. I had NO idea back then about any of this information about corys. I think for many years there must have been widespread simplistic info passed around that these were just nice little "clean-up crew" bottom dwellers to have one or two of..

I'm curious sometimes whether better info would have been out there if I'd found the right books? Do you remember your sources of information in the 60's?

~~waterdrop~~

 

[nmonks]

This is an interesting question. While I wasn't even alive in the 60s, many of the books I read starting out in the hobby were written then, or else during the 1970s, when things weren't very different. What I think has changed is that around about 1980 the hobby changed from being about simply keeping things *alive* to keeping them *well*. The range of species kept increased dramatically, and the shift of focus went from species that were hardy but not necessarily beautiful (spanner barbs for example) through to much more delicate but prettier species (such as cardinal tetras).

Some of my older books recommend water changes of 10-20% per month, an amount that sounds negligent by modern standards. But given the hardiness of the fish, the risk of exposing them to sudden changes in water chemistry was perhaps more serious than chronically high nitrate levels. Since tanks were left for long periods with minimal water changes -- the idea the "mature" water was better was very widely held -- tanks tended towards becoming acidified. A big water change could suddenly switch a tank from acidic to basic, potentially stressing the fish. This is also where carbon came into play, since it removed the yellow colour old water develops. It's a cosmetic benefit more than anything else, but useful in context. As I've stated endlessly on this forum, with large, regular water changes carbon is largely redundant in freshwater tanks, and for inexperienced hobbyists, the risk of leaving carbon in the tank when treating for Ick or Finrot is, I think, outweighs any benefits carbon provides.

In any event, because we keep more delicate fish, and we expect them to live longer, so we need to be more careful about how to keep them. To quote Lincoln, "The dogmas of the quiet past are inadequate to the stormy present".

Cheers, Neale

I'm curious sometimes whether better info would have been out there if I'd found the right books? Do you remember your sources of information in the 60's?

 

[rebrn]

Thanks guys, I had found the Pygmy Cories after I had posted this and as they are a smaller cory species I think I should be ok to add 5 to the 12 gallon. I was concerened about overstocking, but it sounds like I should be ok to add the 5 or 6 Pygmy Corries with the 9 Harlequin Rasboras and the 2 Nerite snails. Now I just need to find somewhere to buy them. I did find one place that sells them but you have to buy 10 of them and I think that is just too much in the 12 gallon with the current stock. I suppose I could split them and put 5 in my 5 Gallon with the Betta and the Nerite snail, but again, I think that would put me in an overstock situation and I really don't want to do that. I suppose I will just keep looking, I am in no rush, I don't need them as a clean up crew (although that is an added bonus) I really want them to add a little interest to the bottom of the tank, the harlequins stay at the middle to upper levels and the bottom just looks bear. I already have a sand substrate so no issues there, just have to find the little guys.

Thanks again.

 

[waterdrop]

ahh, interesting! Thanks! WD

 

[nmonks]

As stated above, I would *strongly* suggest against keeping just five or six Corydoras habrosus, Corydoras pygmaeus or Corydoras hastatus. Trust me on this: you will regret it. These are entirely different fish when kept in big groups. Kept in tiny groups, they just don't do well, and you may as well not get any for all the good they'll do. All that'll happen is they'll disappear among the plants. In a 12-gallon tank a group of ten tiny Corydoras will work fine, and you could easily add a school of eight or more appropriately tiny midwater fish (such as Boraras spp.).

Nerites should be kept about one per 5 gallons. If you add too many, all that happens is that the surplus will starve to death. These snails don't "clean up" anything: they eat green algae and diatoms. So far as I know, they don't even go for algae wafers. So you really must plan around their feeding requirements. Cherry shrimps are much better all-purpose bottom feeders, since they eat some algae as well as organic detritus of all types.

Cheers, Neale

 

[rebrn]

I got the nerites because I do have an algae problem in all my tanks. It is not a huge algae problem but large enough that simple scurbbing and water changes were not making a dent, that is why I have kept it to a minimum of 1 in the 5 gallon, 2 in the 12 gallon (worst off all the tanks with algae) and 7 in the 55 gallon, and as an FYI they do go for the algae wafers, at least mine do, the one in the 5 gallon did such a good job that he was out of food in a week, I put an algae wafer in there and he gobbled it up. The snails in the 12 gallon really do need to stay as that is the worst of all the tanks for algae, even the 2 snails are having a hard time keeping up. I don't know what it is about that particular tank, but I would scrub every thing clean, do my weekly water change and the next day (not even sometimes later that same day) the algae was back. So with out the snails there is just no way I could keep up. The other two tanks would probably be fine without the snails, but I had to order 10 so I put 1 in the 5 gallon and rest in the 55 gallon. They seem to be doing great, I have had them in there for a little over a week and they are still going strong. I have only had to supplement the 1 in the 5 gallon once so far.
Also, I don't have a problem having more cories I just thought that having 10 cories plus 9 rasboras and 2 snails was too much in the 12 gallon tank. I don't want to be in an overstock situation, I would rather not get them then put them into an overstock situation. I don't particularily want them as a clean up crew, I don't have any issues with left over food that the tank maintaince I do won't take care off.I simply wanted something to add to the bottom of the tank for interest. I have 6 skunk cories in my 55 gallon, and they are doing great, they school togethor, and can are seen all the time, usually at the bottom, but occasionally in the middle of the tank. I just think they are interesting fish, and thought it would be nice to have some in the 12 gallon, but as Skunks will get too big for the 12 gallon I thought I would try the pygmies.